PITTSBURGH -- The Pittsburgh Steelers improved to 7-2 Sunday by beating the Indianapolis Colts, and they hardly have a chance to catch their breath before facing another AFC South foe. The Tennessee Titans visit Heinz Field Thursday night in another important conference game.

The Steelers and Patriots are tied atop the AFC with seven weeks remaining in the regular season, but the Titans are close behind at 6-3.

The biggest issue this week as the Steelers prepare for the Titans is their secondary. They'll likely be without two starters after cornerback Joe Haden and safety Mike Mitchell were injured against the Colts.

Haden is out indefinitely with a fractured fibula and Mitchell has an ankle injury that did not allow him to return after exiting Sunday's game early in the third quarter.

Veteran Coty Sensabaugh took over for Haden and played the final three quarters at Haden's outside corner position. Robert Golden filled in for Mitchell at safety.

"It definitely hurts when you lose Joe and Mike," linebacker Ryan Shazier said. "Those two guys are great making plays for us. We believe in Coty and Rob when they come in the game."

The Steelers had the second-ranked pass defense in the NFL entering the Colts game. And despite giving up two big passing plays of 60 and 61 yards for touchdowns, the Colts still only managed 222 yards passing. That's about 40 yards over the Steelers' average, but it's still a respectable number given they had to play about half the game without two starters.

Defensive end and team captain Cameron Heyward said the front seven might have more responsibility with Haden and possibly Mitchell out of the lineup.

"We might have to pick it up in the front seven a little bit," he said. "The first half was not indicative of how we want to play. If there are injuries, guys have to step up, not only in the back end but front end, too. We have to get more pressure. We have to get ourselves in better situations where we can light our hair on fire and get to the quarterback."

The winner of the Steelers-Titans game will be in great position to challenge the Patriots for the top seed in the AFC, while the loser will have an uphill climb to get the top spot.

"At the end of the day, I don't think anyone likes short weeks," Shazier said. "Everyone loves prime time, you know, you like to be the only ones on TV, but it kind of stinks sometimes playing two games in (five days). Other sports have to it also. It's part of the game. We're going to go out there, practice, get the game plan and we just need to be more focused this week than we ever have."

--It's looking more and more like the Steelers' defense is going to have to carry the team into the postseason. The offense continues to struggle scoring while the defense continues to limit opponents' scoring.

After giving up 17 points in the first 32 minutes of the game Sunday, the defense pitched a shutout over the final 28 minutes to help the Steelers secure the win. It was the seventh time in the first nine games the Steelers have given up 18 points or fewer.

"I feel like when the defense is on, when we want to play, man, we're on," second-year safety Sean Davis said. "We didn't give up any points in the second half. We can do that all four quarters. We're our own worst enemy. That's how I feel about this defense. I don't feel like anyone can touch us. When we're on, we're on."

The confusion on the Steelers' 2-point conversion typifies what's going on with that unit. The Steelers were forced to call a timeout after a Roethlisberger touchdown pass to Vance McDonald because they could not get aligned correctly. After the timeout, Roethlisberger had to take a delay of game penalty when Martavis Bryant lined up wrong.

In the end, it didn't cost the Steelers because Roethlisberger completed a 7-yard pass to Bryant for the conversion on a different play call. But the miscues are representative of the problems the unit faces.

The Steelers are averaging 20.8 points per game. Their stated goal before the season was to average 30 points per game.

"We have to be better on offense," head coach Mike Tomlin said. "We have to be better winning some third-down situations. We'll get back in the lab and go to work."

NOTES: CB Joe Haden has a fractured fibula in his left leg and has been ruled out for the Thursday night game against the Titans. Head coach Mike Tomlin said the Steelers will not immediately place on Haden on injured reserve because they want to give him an opportunity to play again during the regular season if he is able. Estimates for Haden's return are 4-6 weeks, but Tomlin reiterated Monday that it could be a shorter period or a longer period. They just have to wait to see how the bone heals. ... S Mike Mitchell left the Colts game early in the third quarter with an ankle injury. Head coach Mike Tomlin did not rule Mitchell out for the Titans game. He said there is a chance, albeit a small one, that he can play. ... TE Vance McDonald injured an ankle in Sunday's game and is in the same boat as Mike Mitchell. The team will wait to see how he progresses during the short week.

REPORT CARD VS. COLTS

--PASSING OFFENSE: B -- Ben Roethlisberger was 12 of 16 in the second half, including 4 of 4 on the Steelers' final drive that ended with a game-winning field goal as time expired. It was Roethlisberger's 40th fourth-quarter comeback as the Steelers erased a 17-9 deficit with 11 points over the final 1:52. But the Steelers needed a late comeback because the offense was so inconsistent in the first half. Roethlisberger threw an interception and had a 33.2 passer rating at halftime, when the Steelers trailed 10-3. The Colts doubled Antonio Brown for most of the game, which freed up rookie JuJu Smith-Schuster to catch five passes for 97 yards and a touchdown. Tight end Vance McDonald scored his first touchdown with the Steelers. He was acquired in a trade shortly before the regular season began.

--RUSHING OFFENSE: C-minus -- The Steelers averaged just 2.9 yards per carry against a defense that entered the game 26th in the NFL in rush defense. Le'Veon Bell had 80 yards, but he needed 26 carries to do it. His longest run of the day was 15 yards. The inability to run led to the Steelers having to rely on the pass to win. It worked against the Colts, but the Steelers are going to need a stronger running game to get past better teams.

--PASS DEFENSE: C -- The Steelers gave up touchdown passes of 60 and 61 yards as their second-ranked pass defense showed some cracks for a second consecutive game. Jacoby Brissett finished the game 14 of 24 for 222 yards so the Steelers didn't give up much other than the big plays. It didn't help matters that starting corner Joe Haden left the game in the first quarter with a fractured fibula, or when starting safety Mike Mitchell left the game in the second half with an ankle injury. But the reserves played well in the second half. Coty Sensabaugh filled in for Haden and Robert Golden for Mitchell. Brissett completed just five passes in the second half. The Steelers tightened up when they had to, but giving up big plays is not a recipe for success for a team that's struggled to score.

--RUSH DEFENSE: B -- The Steelers held the Colts to just 2.4 yards per carry thanks to a stifling second-half performance in which the Colts managed just 21 yards on the ground. Frank Gore had some success in the first half, which helped the Colts' offense move the ball and score 10 points. But once the Steelers shut him down in the second half, the game turned in their favor. The Steelers would do well to become a more consistent team when it comes to stuffing the run, but they made the necessary adjustments against the Colts and got a victory on the road.

--SPECIAL TEAMS: B-minus -- The field-goal unit could use some extra practice this week. Chris Boswell had an extra point blocked and missed a 37-yard field goal midway through the fourth quarter when the game was tied. Both miscues might have cost the Steelers the game. The Steelers were able to tie the score and make up the points by converting a 2-point conversion try in the fourth quarter, and Boswell redeemed himself by booting the game-winning 33-yarder as time expired. Consecutive holding penalties on punts forced two re-kicks and cost the Steelers 22 yards in field position in the first quarter. Perhaps the best play by the special teams came from punter Jordan Berry and tight end Jesse James. They hustled after the extra-point block and thwarted a Colts 2-point try when they tackled Matthias Farley 3 yards short of the end zone.

--COACHING: B-minus -- The Steelers almost lost another game against a big underdog, a bugaboo over the years for head coach Mike Tomlin. The Steelers were 10-point favorites and sleepwalked their way through the first half before scoring 17 points in the second half to get the road victory. Give defensive coordinator Keith Butler credit for bringing more pressure in the second half and making Jacoby Brissett uncomfortable. Offensive coordinator Todd Haley continues to struggle with his play-calling, but he also made the necessary adjustments after halftime to get the victory. All in all, it was a win, but the feeling persists that poor game-planning and execution will doom this team against a worthy opponent.